A Study of SYH2069 Injection in Healthy Participants

Inclusion Criteria: * Fully understand the content, process and possible adverse reactions of the trial, and voluntarily sign the informed consent form before the trial; * Male or female, aged 18-55 years (inclusive, based on the time of signing the informed consent form) at screening; * At screening, male body weight ≥ 50 kg, female body weight ≥ 45 kg, SAD study: BMI between 19 and 28 kg/m2 inclusive), MAD study: BMI between 24 and 35 kg/m 2 inclusive); * Subjects (including partners) have no plans to have children from the time of signing the informed consent form until 6 months after the last dose, and agree to use highly effective contraceptive measures specified in the protocol. Exclusion Criteria: * Known or suspected allergies to GLP-1 or GIP receptor agonists or any components of the investigational product, or allergic constitution (allergies to multiple drugs and foods); * Abnormal results of vital signs, physical examination, laboratory tests, chest X-ray, ultrasound, and electrocardiogram, etc., which are judged by the investigator to be clinically significant and unsuitable for participation in the study. Among them, the following conditions were not excluded in the MAD study: (1) systolic blood pressure \<160 mmHg, diastolic blood pressure \<100 mmHg; (2) TG ≤ 3.42 mmol/L, TC ≤ 7.75 mmol/L (regardless of whether LDLC is abnormal), and abnormal HDLC; (3) ALT \< 2 times × upper limit of normal, AST \< 2 times × upper limit of normal, GGT \< 2.5 times × upper limit of normal, total bilirubin \< 1.5 times × upper limit of normal; (4) Blood uric acid \<480 μmol/L and never accompanied by physiological abnormalities (gout, etc.); (5) Ultrasound shows fatty liver and excludes causes other than metabolism; * Meet any of the following at screening: (1) HbA1c \> upper limit of normal, or fasting blood glucose ≤ 3.9 mmol/L or ≥ 6.1 mmol/L; (2) Calcitonin ≥ 50 ng/L; (3) eGFR \< 90 mL/min/1.73m 2; (4) TSH exceeds the normal reference range; * Patients with prolonged QT/QTc interval at screening (QTcF \> 450 ms), or have a history of risk factors for torsades de pointes (such as family history of heart failure/cardiomyopathy or long QT syndrome), or are taking concomitant medications that prolong the QT/QTc interval; * Those who are positive for any of hepatitis B surface antigen, hepatitis C virus antibody, human immunodeficiency virus antibody, and Treponema pallidum antibody; * History or presence of major cardiovascular, respiratory, digestive, urinary, hematological, endocrine, immune or nervous system diseases; * Subjects with severe trauma or major surgery within 6 months prior to screening, or planned to undergo surgery during the trial; * Patients with thyroid nodules diagnosed as C-TIRADS category 3 or above in the past or during the screening period; * Personal or family history of medullary thyroid carcinoma (MTC) or multiple endocrine neoplasia syndrome type 2, or history of pancreatitis or acute or chronic gallbladder disease; * Those with a history of malignant tumors, mental illness, depression, anxiety, or epilepsy; * History of clinical gastric emptying abnormalities (such as gastric outlet obstruction), severe chronic gastrointestinal diseases (such as inflammatory bowel disease, active ulcer); * Previous gastrointestinal surgery leading to malabsorption, or long-term use of drugs that have a direct effect on gastrointestinal motility. e.g., bariatric surgery or procedures (e.g., gastric banding), or use of GLP-1 or GIP receptor agonists or drugs or products that, in the opinion of the investigator, may cause weight change and affect weight assessment within 3 months prior to dosing. * Body weight change ≥ 5% within 3 months prior to screening (inclusive) (only applicable to MAD study； * Those who have symptoms such as dermatitis or skin abnormalities at and around the administration site; * Use of any prescription drugs, over-the-counter drugs, or Chinese herbal medicines within 2 weeks before screening; * Use of drugs that may affect glucose metabolism (e.g., systemic steroids, non-selective beta-blockers, monoamine oxidase inhibitors) within 1 month before screening;